Can vent be reduced in size for clearance?

[DIYorBust]

I know it sounds bad, but here's the deal. I have a 3 inch WC drain individual vented with 2-in pipe. The plumbers overdrilled a 2x4 stud to get the 2 inch through it. Well since it's a bearing wall at that point, it turns out this is creating a problem. A 1.5 inch pipe could pass the stud without drilling more than 60% and I believe this is acceptable if we double the stud.


So given that a 1.5" vent is large enough to vent the WC, can I replace just the section passing the stud with 1.5", or do I need to replace it all the way from that point down to the drain?

Thanks DIY

 

[James Henry]

I did the exact same thing. Just replace the horizontal section. Doesn't matter.

 

[Sponsor]

 

[Sylvan]

11/2 is Legal in NYC (Old code) You cannot decrease the vent or waste BUT you can use 11/2" pipe for a WC Vent no problem

 

[Tuttles Revenge]

I suppose the only real downside is if the next plumber ties into what they think is a 2" vent but its really necked down to 1.5... The house would probably explode.

 

[DIYorBust]

I suppose the only real downside is if the next plumber ties into what they think is a 2" vent but its really necked down to 1.5... The house would probably explode.

Ha, I thought about that. But at this location, it's pretty much impossible anyone would tie anything into that vent, and additionally they would have to tie in more than 8 total dfus for it to matter and even then nothing would explode as you say.

 

[Sylvan]

11/2 Vent run up to 150 feet can service up to 8 FU

11/2 vent 100 feet can handle 10 FU


I doubt very seriously all the fixtures will be used at the same time

 

[WorthFlorida]

You can use a stud shoe and keep the 2" vent. Using the correct fasteners and quantity the stud will retain its load rating.

https://www.fastenersplus.com/produ...MI2IXSv9mj8QIVCbbICh2mXwlOEAQYASABEgLiuvD_BwE

https://cdn.shopify.com/s/files/1/0277/8644/4936/files/HSS-SS-Stud-Shoes.pdf?v=1519474738932404799